Personal armor resistant to pointed or sharp weaponry

ABSTRACT

According to exemplary inventive practice, a personal armor system includes a textile-based layer not exceeding ½-half-inch thickness, and an elastomeric coating not exceeding ⅛-inch thickness. The textile-based layer includes a fiber reinforcement and a resin binder. The combined areal density of the textile-based layer and the elastomeric coating does not exceed 2.5 psf. According to a first mode of inventive practice, the elastomeric coating is essentially a strain-rate-sensitivity-hardening elastomer, and the areal density of the textile-based layer does not exceed 2.3 psf. According to a second mode of inventive practice, the elastomeric coating is essentially a microparticle-filled strain-rate-sensitivity-hardening elastomeric matrix material, and the areal density of the textile-based layer does not exceed 1.7 psf. The microparticles (e.g., spherical glass microparticles) do not exceed, by weight, 30 percent of the strain-rate-sensitivity-hardening elastomeric matrix material. The textile-based layer affords ballistic protection; the elastomeric coating affords protection against sharp/pointed objects.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional application No.62/802,992, filed 8 Feb. 2019, hereby incorporated herein by reference,entitled “Personal Armor Resistant to Sharp or Pointed Weaponry,” jointinventors James Pinsky, Philip J. Dudt, and Devin P. Murphy.

This application is related to U.S. nonprovisional application entitled“Personal Armor Resistant to Sharp or Pointed Weaponry,” being filedconcurrently herewith and hereby incorporated herein by reference, jointinventors James Pinsky, Philip J. Dudt, and Devin P. Murphy, Navy CaseNumber 103,820.

STATEMENT OF GOVERNMENT INTEREST

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION

The present invention relates to armor, more particularly to personalarmor (e.g., body armor and helmets) that protects against penetrationby sharp or pointed objects such as stabbing instruments (e.g., knivesand bayonets) and some types of projectiles (e.g., arrows andflechettes).

Ballistic fabrics are notable among the materials that are commonly usedin conventional protective armors. Ballistic fabrics typically have awoven or laminate construction and are made of advanced syntheticfibrous/textile materials such as Kevlar®, Twaron®, Spectra®, Dyneema®,and Zylon®. Examples of high-performance ballistic fibers are aramid,polyethylene, polyamide, polyester, polybenzobisoxazole, and glass. Alightweight ballistic fabric can defeat a projectile by “catching” itthrough large levels of extension. Ballistic fabrics are used, forinstance, in helmets and lightweight body armor (e.g., vests) and forprotecting ship spaces. In addition, low weight protective shields havebeen made for protection in complex environments.

Also commonly used in conventional protective armors are ceramicmaterials. A ceramic plate or insert operates by breaking up aprojectile with a hard surface. Typically, a spall composite layer isprovided behind the comminuted ceramic to catch the projectile fragmentsand ceramic particles.

Many ballistic fabrics are vulnerable in their susceptibility topenetration (e.g., cut, slash, slice, stab, or puncture) by knives,blades, swords, bayonets, arrows, flechettes, ice picks, spikes, awls,needles, sharp/pointed explosive fragments, and other sharp or pointedobjects. For instance, police and special ops are vulnerable to attackby hunting arrows that are razor sharp and can cut through even thestrongest Kevlar®; this threat is especially prevalent in jungles andother densely forested areas. Hand-held items such as knives, ice picks,“shivs,” etc., pose threats in prison and other dangerous environments.

It is generally understood in the personal armor-related arts that anarmor system designed to protect against a particular threat may not beeffective against another type of threat. For instance, woven fabricsthat are designed to afford ballistic protection differ from wovenfabrics that are designed to afford stab resistance. See, e.g., Paul V.Cavallaro, “Soft Body Armor: An Overview of Materials, Manufacturing,Testing, and Ballistic Impact Dynamics,” Naval Undersea Warfare CenterDivision, Newport, Rhode Island, NUWC-NPT Technical Report 12,057, 1Aug. 2011 (Approved for public release; distribution is unlimited),incorporated herein by reference.

Generally speaking, textiles for ballistic protection are less densely(more loosely) woven in order that there be sufficient mobility of theyarns to prevent premature failure upon impact of the projectile. On theother hand, textiles for stab resistance are more densely (more tightly)woven in order that the yarns not be pushed aside upon impingement bythe sharp or pointy object. It is thus seen that, with respect toballistic protection vis-A-vis stab resistance, the design criteria forpersonal armor are incongruous. Ballistic textile will tend to performunsatisfactorily for stab resistance, and stab-resistant textile willtend to perform unsatisfactorily for ballistic protection. Similarly,commercially available nonwoven laminates having unidirectional fibers,such as Dyneema® or Spectra Shield®, are optimized for ballisticprotection but will be lacking in performance against sharp or pointedobjects.

In a variety of contexts, the dual threats exist of (i) ballisticpenetration and (ii) sharp-pointed or sharp-edged penetration. Personalarmor systems are typically designed to protect against either shootingor stabbing, but not against both kinds of threats. For instance, anarmor system devised to protect against bullets may not affordsufficient protection against knives and the like. Multi-threat personalarmors have been conceived that are designed to protect against varioustypes of threats. Solutions have been proposed that integrate ballisticprotective armor with cutting/stabbing protective armor.

A notable approach to multi-threat protection is disclosed by Norman J.Wagner and Eric D. Wetzel in the following U.S. patents, each of whichis hereby incorporated herein by reference: U.S. Pat. No. 7,226,878 B2,entitled “Advanced Body Armor Utilizing Shear Thickening Fluids”; U.S.Pat. No. 7,498,276 B2, entitled “Advanced Body Armor Utilizing ShearThickening Fluids”; U.S. Pat. No. 7,825,045 B1, entitled “Advanced BodyArmor”. Wagner et al. disclose a kind of “liquid armor” technology.According to Wagner et al., a “shear thickening fluid” includes acarrier (e.g., ethylene glycol) with particles suspended in the liquidcarrier. A ballistic fabric is infused with and holds the shearthickening fluid. While held within the fabric, the shear thickeningfluid stiffens when impacted by a sharp/pointed object, therebydefeating the impacting object.

Among the drawbacks of Wagner et al.'s methodology is the likelihoodthat the shear thickening fluid will degrade over time if notsafeguarded from the atmosphere. Furthermore, the shear thickening fluidis effective over a limited range of penetrator velocities and cannotaddress all of the threats. The liquid armor technology spawned byWagner et al. has been considered and tested by the U.S. military forimplementation in various suits of armor, such as “iron man” exoskeletonsuits and tactical assault light operator suits.

SUMMARY OF THE INVENTION

In view of the foregoing, an object of the present invention is toprovide an armor that defeats both (i) ballistic impacts and (ii)sharp-edged or sharp-pointed impacts.

An exemplary embodiment of an inventive composite armor system includesa ballistic fabric-based component and an elastomeric material. Theballistic fabric-based component is characterized by an aerial arealdensity no greater than approximately 2.3 pounds per square foot. Theelastomeric material consists essentially of astrain-rate-sensitivity-hardening elastomer, and covers at least onearea of the ballistic fabric-based component. In the at least one areaof the ballistic fabric-based component, the elastomeric material andthe ballistic fabric-based component, in combination, are characterizedby an aerial areal density no greater than approximately 2.5 pounds persquare foot.

Another exemplary embodiment of an inventive composite armor systemincludes a ballistic fabric-based component and an elastomeric material.The ballistic fabric-based component is characterized by an aerial arealdensity no greater than approximately 1.7 pounds per square foot. Theelastomeric material consists essentially of a particle-filledstrain-rate-sensitivity-hardening elastomeric matrix material, andcovers at least one area of the ballistic fabric-based component. Theparticle-filled strain-rate-sensitivity-hardening elastomeric matrixmaterial is characterized by a combination of an elastomer matrix and aquantity of particles in the elastomer matrix, wherein the quantity ofparticles by weight constitutes no greater than approximately 50 percentof the elastomer. In the at least one area of the ballistic fabric-basedcomponent, the elastomeric material and the ballistic fabric-basedcomponent, in combination, are characterized by an aerial areal densityno greater than approximately 2.5 pounds per square foot.

According to an exemplary embodiment of an inventive method forenhancing armor, a personal armor device is provided that includes aballistic fabric-based component. The ballistic fabric-based componentis characterized by an aerial areal density no greater thanapproximately 2.3 pounds per square foot. At least one area of theballistic fabric-based component is covered with an elastomericmaterial, which consists essentially of astrain-rate-sensitivity-hardening elastomer. The covering of the atleast one area is performed so that, in the at least one area, theelastomeric material and the ballistic fabric-based component, incombination, are characterized by an aerial areal density no greaterthan approximately 2.5 pounds per square foot.

According to another exemplary embodiment of an inventive method forenhancing armor, a personal armor device is provided that includes aballistic fabric-based component. The ballistic fabric-based componentis characterized by an aerial areal density no greater thanapproximately 1.7 pounds per square foot. At least one area of theballistic fabric-based component is covered with an elastomericmaterial, which consists essentially of a particle-filledstrain-rate-sensitivity-hardening elastomeric matrix material, which ischaracterized by a combination of an elastomer matrix and a quantity ofparticles in the elastomer matrix, wherein the quantity of particles, byweight, constitutes no greater than approximately 50 percent of theweight of the elastomer matrix. The covering of the at least one area isperformed so that, in the at least one area, the elastomeric materialand the ballistic fabric-based component, in combination, arecharacterized by an aerial areal density no greater than approximately2.5 pounds per square foot.

According to exemplary inventive practice, a relatively thin coating ofa strain-rate-sensitivity-hardening elastomer is provided on a ballisticfabric-based component (e.g., a helmet, vest, or sleeve) in order toenhance the ballistic armor component with an ability to defeat pointedor sharp-cutting projectiles and instruments. The present invention'sballistic fabric-based component is protective against ballisticimpacts. In addition, the present invention's elastomeric coating isprotective against sharp-pointed or sharp-edged impacts. According to anexemplary inventive body armor, the elastomeric material imparts stabresistance but does not “weigh down” the body armor and does notcompromise the ballistic protection of the underlying fabric layer.

Generally speaking, it is desirable for a personal armor to berelatively lightweight in order to be comfortably worn on a person'shead or body. A key feature of exemplary inventive practice is thethinness, and hence lightweightness, of the elastomeric coating. Theelastomeric coating of an exemplary inventive embodiment issignificantly thinner than its ballistic fabric-based component. Theelastomeric coating is the face component of an exemplary inventivearmor system. The thinness characterizing the inventive armor'selastomeric coating is functionally significant in protecting againstvarious kinds of weaponry. The material, physical, and dimensionalqualities of the elastomer serve to afford resistance to sharp/pointedweaponry and garment practicality (particularly in terms of weight,shape, and bulkiness), while permitting ballistic protection by theunderlying fabric-based component.

Exemplary inventive embodiments are protective against plural/multiplethreats. An inventive armor is resistant to ballistics because of theballistic fabric-based component, and is resistant to cutting orpuncturing by sharp or pointed implements and ammunition because of theelastomeric coating. The present invention defends against projectilesand implements that are penetrative by virtue of their sharp-pointed orsharp-edged configuration. An inventive armor may be efficaciouslyembodied, for example, as soft body armor (e.g., a vest or sleeve) or ahelmet. As exemplarily embodied, an inventive armor represents apractical, low-cost, durable methodology for defeating threats fromsharp-edged/pointed hand weapons, or from flechettes and othersharp-edged/pointed weapons traveling at higher velocities.

Unlike conventional armor systems, an exemplary inventive armor systemcan afford protection over a broad range of velocities. Furthermore, anexemplary inventive device does not require maintenance, resulting incost savings for SOCOM (U.S. Special Operations Command) and other typesof armor suits. Items suitable for application of the inventivetechnology include but are not limited to helmets, ballistic fabric vestplates (such as containing electronic gear), and equipment cowls andfairings for protecting underlying equipment. The present invention canbe embodied to protect a human's torso, limbs, and/or head, or toprotect inanimate objects.

Exemplary inventive practice utilizes astrain-rate-sensitivity-hardening elastomer such as disclosed by thefollowing United States patents, each of which is hereby incorporatedherein by reference. These references are informative with regard tostrain-rate-sensitivity-hardening elastomers and their physicalproperties: U.S. Pat. No. 9,869,533 B2 to Vanarsdalen et al. entitled“Blast and Ballistic Improvement in Helmets”; U.S. Pat. No. 8,580,387 B1to Fedderly et al. entitled “Polyurea Composite Armor”; U.S. Pat. No.7,946,211 B1 to Winchester et al. entitled “Electrical and ElastomericDisruption of High-Velocity Projectiles”; U.S. Pat. No. 7,938,053 B1 toDudt et al. entitled “Armor”; U.S. Pat. No. 7,794,808 B2 to Dudt et al.entitled “Elastomeric Damage-Control Barrier”; U.S. Pat. No. 7,300,893B2 to Barsoum et al. entitled “Armor Including a Strain Rate HardeningElastomer”; U.S. Pat. No. 7,114,764 B1 to Barsoum et al. entitled “Mineand Collision Protection for Passenger Vehicle”. Types of elastomersthat may be suitable for inventive practice of astrain-rate-sensitivity-hardening elastomer include polyurea,polyurethane, or a combination (e.g., mixture) of polyurea andpolyurethane.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of example, withreference to the accompanying drawings, wherein like numbers indicatesame or similar parts or components, and wherein:

FIG. 1 is a cross-sectional view of an embodiment of inventive armor.The inventive armor includes a strain-rate-sensitivity-hardeningelastomer coating (such as a polyurea) and a ballistic fabric (such as aKevlar® material). FIGS. 1 through 4 are similar cross-sectional viewsof various embodiments of inventive armor.

FIG. 2 shows an embodiment of inventive armor that includes astrain-rate-sensitivity-hardening elastomer coating (such as a polyurea)and a ballistic fabric (such as a Kevlar® material), wherein a portionof the elastomer coating infiltrates the ballistic fabric.

FIG. 3 shows an embodiment of inventive armor that includes aparticle-filled strain-rate-sensitivity-hardening elastomeric matrixmaterial coating (such as a polyurea filled with microparticles, e.g.,glass microspheres) and a ballistic fabric (such as a Kevlar® material).

FIG. 4 shows an embodiment of inventive armor that includes aparticle-filled strain-rate-sensitivity-hardening elastomeric matrixmaterial coating (such as a polyurea filled with microparticles, e.g.,glass microspheres) and a ballistic fabric (such as a Kevlar® material),wherein a portion of the particle-filledstrain-rate-sensitivity-hardening elastomeric matrix material coatinginfiltrates the ballistic fabric.

FIGS. 5 through 8 are cutaway top plan views of the embodiments ofinventive armor shown in FIGS. 1 through 4 , respectively.

FIGS. 9 through 11 are representations, based on photographic images, ofthree broadhead arrows that were used by the present inventors in theirtesting of the present invention.

FIG. 12 is a diagram illustrating, by way of example of conventionalballistic armor, an intact penetration of an impelled broadhead arrowthrough a ballistic fabric.

FIG. 13 is a diagram illustrating, by way of example of an inventiveballistic armor, a ricochet of an impelled broadhead arrow off of astrain-rate-sensitivity-hardening elastomer coating coupled withballistic fabric.

FIG. 14 is a diagram illustrating, by way of example of an inventiveballistic armor, a ricochet of an impelled broadhead arrow off of aparticle-filled strain-rate-sensitivity-hardening elastomeric matrixmaterial coupled with ballistic fabric. FIGS. 13 and 14 are similar.

FIG. 15 is a diagram illustrating, by way of example of an inventiveballistic armor, a broken penetration of an impelled broadhead through astrain-rate-sensitivity-hardening elastomer coating coupled withballistic fabric.

FIG. 16 is a diagram illustrating, by way of example of an inventiveballistic armor, a broken penetration of an impelled broadhead through aparticle-filled strain-rate-sensitivity-hardening elastomeric matrixmaterial coupled with ballistic fabric. FIGS. 15 and 16 are similar.

FIG. 17 is a table setting forth various respective thicknesses of anelastomeric coating and a ballistic fabric, and various correspondingthickness-to-thickness ratios, in accordance with exemplary practice ofthe present invention.

FIG. 18 is a table setting forth the elastomeric coating thicknessranges and the ballistic fabric aerial areal density ranges for twomodes of inventive practice, viz., (i) an inventive armor systemincluding a strain-rate-sensitivity-hardening elastomer coating, and(ii) an inventive armor system including a particle-filledstrain-rate-sensitivity-hardening elastomeric matrix material coating.

DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION

Referring now to FIGS. 1 through 8 , according to exemplary practice ofthe present invention an elastomeric coating forms an integral shellthat resists penetration by sharp and pointed objects. Depending on theinventive embodiment, the elastomeric coating can be: either (i) anunfilled strain-rate-sensitivity-hardening elastomer (e.g., polyurea orother polymer) coating 10, such as shown in FIGS. 1, 2, 5, and 6 ; or(ii) a particle-filled strain-rate-sensitivity-hardening elastomeric(e.g., polyurea or other polymer) matrix coating 30, such as shown inFIGS. 3, 4, 7, and 8.

The elastomer (e.g., polyurea) in elastomeric coating 10 or 30,according to exemplary inventive practice, is a polymer from a class ofpolymers that exhibit highly rate-sensitive behavior over a wide rangeof velocities. The physical properties of a polyurea or other polymerthat may be suitably used for inventive practice of an elastomericcoating 10 or an elastomeric coating 30 are disclosed in theaforementioned U.S. Pat. Nos. 9,869,533 B2, 8,580,387 B1, 7,946,211 B1,7,938,053 B1, 7,794,808 B2, 7,300,893 B2, and 7,114,764 B1, each ofwhich is incorporated by reference in the instant disclosure.

As the terms are used herein, (i) a “strain-rate-sensitivity-hardeningelastomer coating” and (ii) a “particle-filledstrain-rate-sensitivity-hardening elastomeric matrix material coating”are two types of “elastomeric coating” that are used in accordance withexemplary practice of the present invention. Otherwise expressed, (i) a“strain-rate-sensitivity-hardening elastomer” and (ii) a“particle-filled strain-rate-sensitivity-hardening elastomeric matrixmaterial” are two types of “elastomeric material” that is used inaccordance with exemplary practice of the present invention. Astrain-rate-sensitivity-hardening elastomer coating is unadulterated,i.e., unfilled. According to exemplary inventive practice of aparticle-filled strain-rate-sensitivity-hardening elastomeric matrixmaterial coating, the particles are microparticles, for instance,spherical microparticles such as made of a glass material. Aparticle-filled strain-rate-sensitivity-hardening elastomeric matrixmaterial is a strain-rate-sensitivity-hardening elastomer coating thatis filled with particles to a weight that, according to exemplaryinventive practice, is 50% or less of the weight of thestrain-rate-sensitivity-hardening elastomer material.

For instance, by way of example of inventive practice, a polyureacontains a quantity of particles filled (e.g., spherical glassmicroparticles) to a weight that is 30% or less of the weight of thepolyurea. According to exemplary embodiments of the present invention, aparticle-filled strain-rate-sensitivity-hardening elastomeric matrixmaterial represents a combination of a strain-rate-sensitivity-hardeningelastomer material and a quantity (e.g., multiplicity) of particles(e.g., microparticles) wherein the quantity of particles has a weight inthe approximate range of 10% to 30% of the weight of thestrain-rate-sensitivity-hardening elastomer material.

As shown in FIGS. 1 and 5 , a relatively thinstrain-rate-sensitivity-hardening elastomer (e.g., polyurea) coatinglayer 10 is bonded onto the top surface of a ballistic-fabric-basedcomponent 20 “backing,” thereby establishing an interface 12therebetween in a layered configuration of inventive armor.Strain-rate-sensitivity-hardening elastomer coating 10 at leastsubstantially consists of strain-rate-sensitivity-hardening elastomermaterial 100, and is thin in comparison with the thickness ofballistic-fabric-based layer component 20. Interface 12 represents ademarcation between elastomeric coating layer 10 andballistic-fabric-based component 20. FIGS. 1 and 5 thus illustrate aninventive embodiment in which there is a clear delineation (separation)between elastomeric coating layer 10 and ballistic-fabric-basedcomponent 20. Examples of commercially available fabrics that may besuitably used for inventive practice of ballistic-fabric-based component20 include Kevlar®, Twaron®, Spectra®, Dyneema®, Cordura®, and Zylon®.

In contrast to FIGS. 1 and 5 , FIGS. 2 and 6 illustrate an inventiveembodiment characterized by a degree of infiltration (permeation) of thestrain-rate-sensitivity-hardening elastomer coating 10 into theballistic-fabric-based layer component 20. Accordingly,strain-rate-sensitivity-hardening elastomer coating 10 andballistic-fabric-based layer component 20 overlap (intersect) to form aninfiltration region 21, which represents both a sublayer ofstrain-rate-sensitivity-hardening elastomer coating 10 and a sublayer ofballistic-fabric-based layer component 20. Infiltration region 21includes strain-rate-sensitivity-hardening elastomer material 100 andballistic-fabric-based material 200.

It may be considered that, as shown in FIGS. 2 and 6 ,strain-rate-sensitivity-hardening elastomer coating 10 includes twoadjacent sublayers, viz., an elastomeric sublayer n and an infiltrationsublayer 21. Similarly, it may be considered that ballistic-fabric-basedlayer component 20 includes two adjacent sublayers, viz., a fabric-basedsublayer 22 and an infiltration sublayer 21. Infiltrationregion/sublayer 21 is a combination including elastomeric coating 10 andballistic-fabric-based component 20; that is, infiltrationregion/sublayer 21 includes strain-rate-sensitivity-hardening elastomermaterial 100 and ballistic-fabric-based material 200.

As distinguished from the exemplary inventive embodiments shown in FIGS.1, 2, 5, and 6 , the exemplary inventive embodiments shown in FIGS. 3,4, 7, and 8 include a particle-filled strain-rate-sensitivity-hardeningelastomeric (e.g., polyurea) matrix coating 30 that contains a plethoraof microparticles 50, such as glass microspheres. The inventiveembodiment of FIGS. 1 and 5 is analogous to the inventive embodiment ofFIGS. 3 and 7 insofar as the elastomeric coating does not infiltrateinto the ballistic-fabric-based component 20.

The inventive embodiment of FIGS. 2 and 6 is analogous to the inventiveembodiment of FIGS. 4 and 8 insofar as the elastomeric coatinginfiltrates into the ballistic-fabric-based component 20. Likeinfiltration region 21 (shown in FIGS. 2 and 6 ), infiltration region 23(shown in FIGS. 4 and 8 ) is filled with plural (e.g., multiple)microspheres 50. Infiltration region 21 includesstrain-rate-sensitivity-hardening elastomer material 100 andballistic-fabric-based material 200; in contrast, infiltration region 23includes particle-filled strain-rate-sensitivity-hardening elastomericmatrix material 300 and ballistic-fabric-based material 200.

As shown in FIGS. 3 and 7 , particle-filled elastomeric (e.g., polyurea)matrix coating layer 30 is bonded onto the top surface ofballistic-fabric-based component 20 “backing,” thereby establishing aninterface 32 therebetween in a layered configuration of inventive armor.The particle-filled elastomeric matrix coating layer 30 is thin incomparison with the thickness of ballistic-fabric-based layer component20. Interface 32 represents a demarcation between elastomeric coatinglayer 30 and ballistic-fabric-based component 20. FIGS. 3 and 7 thusillustrate an inventive embodiment in which there is a clear delineation(separation) between elastomeric coating layer 30 andballistic-fabric-based component 20.

FIGS. 4 and 8 illustrate an inventive embodiment characterized by adegree of infiltration (permeation) of the particle-filled elastomericmatrix coating 30 into the ballistic-fabric-based layer component 20.Particle-filled strain-rate-sensitivity-hardening elastomeric (e.g.,polyurea) matrix coating 30 and ballistic-fabric-based layer component20 overlap (intersect) to form an infiltration region 23, whichrepresents both a sublayer of particle-filledstrain-rate-sensitivity-hardening elastomeric matrix coating layer 30and a sublayer of ballistic-fabric-based layer component 20.

The ordinarily skilled artisan who reads the instant disclosure willappreciate that an elastomeric coating material 10/30 does not need tobe directly infused into the underlying fabric material 20 in order tobe infiltrative into fabric material 20. Rather, a relatively smallquantity of elastomeric coating material 10/30 may infiltrate fabricmaterial 20 when the elastomeric coating material 10/30 is exteriorlycoupled (e.g., bonded) with fabric material 20.

It may be considered that particle-filledstrain-rate-sensitivity-hardening elastomeric matrix coating 30 includestwo adjacent sublayers, viz., an elastomeric sublayer 33 and aninfiltration sublayer 23. Similarly, it may be considered thatballistic-fabric-based layer component 20 includes two adjacentsublayers, viz., a fabric-based sublayer 22 and an infiltration sublayer23. Infiltration region/sublayer 23 is a combination includingelastomeric coating 30 and ballistic-fabric-based component 20; that is,infiltration region/sublayer 23 includes particle-filledstrain-rate-sensitive elastomeric matrix material 300strain-rate-sensitivity-hardening elastomer material 100 andballistic-fabric-based material 200.

FIGS. 1 through 4 each illustrate a laminar construction of theballistic-fabric-based component 20, characterized by eleven plies 29.Ballistic-fabric-based material 200 is, for instance, afiber-reinforced, resin-bound material. Many conventional helmets andother protective gear are fiber-reinforced polymer matrix composites(PMCs) containing a high volume fraction of fibers (e.g., fabrics). Aconventional ballistic protective helmet is typically characterized by alow polymeric (e.g., resin) matrix content and a fibrous configuration,somewhat akin to that of an upside-down bird's nest, wherein the fibersact to “catch” a bullet. Ballistic PMCs commonly contain fibers of 80 ormore percent by volume, and contain relatively little polymeric matrixmaterial (e.g., resin binder), for instance on the order of 15 percentby volume.

According to frequent inventive practice of infiltrative embodiments,the elastomeric coating 10/30 at least substantially infiltrates thefirst ply 29; that is, infiltration region 21 or 23 extends throughapproximately the entire width of the front-most ply 29. In exemplaryinventive practice, a low amount of a resinous constituent inconjunction with a ballistic fibrous constituent in aballistic-fabric-based material 200 may allow an elastomeric material100 to penetrate, to a significant degree, into the underlyingsubstrate, viz., the ballistic-fabric-based material 200, therebyforming a more rigid top surface of the elastomeric coating.Ballistic-fabric-based material 200 is characterized by plies (layers)29 and a minimal resin content of 14 to 20 percent, by way of example.The low resin content may permit infusion of elastomeric material 100into at least the first ply 29 of a ballistic-fabric-based material 200.

With reference to FIGS. 9 through 16 , according to exemplary practiceof the present invention an elastomeric coating 10/30 forms an integralshell that resists penetration by sharp and pointed objects. Dependingon the inventive embodiment, the elastomeric coating can be an unfilledelastomeric (e.g., polyurea) coating 10 (such as shown in FIGS. 1, 2, 5,and 6 ) or a particle-filled elastomeric (e.g., polyurea) matrix coating30 (such as shown in FIGS. 3, 4, 7, and 8 ). FIGS. 12 through 16 eachillustrate an example of an impelled arrow 40 impacting an armor system.FIG. 12 shows an example of interaction of an arrow 40 with aconventional ballistic armor system. FIGS. 13 through 16 each show anexample of interaction of an arrow 40 with an inventive ballistic armorsystem.

As distinguished from an exemplary inventive ballistic armor system, aconventional ballistic armor system includes a ballistic fabric material20 and does not include any strain-rate-sensitivity-hardeningelastomeric material. As shown by way of example in FIG. 12 , impelledarrow 40 moving in direction d transpierces a conventional ballisticfabric armor 20. Arrowhead 401, or a substantial portion thereof,penetrates completely through conventional fabric armor 20 and ismanifestly injurious to the individual who is wearing the conventionalfabric armor 20.

Unlike a conventional ballistic fabric armor, an exemplary inventivearmor is capable of resisting both bullets and arrows. FIGS. 13 and 15each depict impingement of an arrow 40 upon an inventive armorembodiment having an unfilled strain-rate-sensitivity-hardeningelastomer coating 10. FIGS. 14 and 16 each depict impingement of anarrow 40 upon an inventive armor embodiment having a particle-filledstrain-rate-sensitivity-hardening elastomeric matrix material coating30. In contrast to conventional ballistic fabric armor systems, anexemplary inventive armor system includes not only a ballistic fabricmaterial 20 but also includes, associated therewith, astrain-rate-sensitivity-hardening elastomeric material 10 or 30.

The present invention's ballistic fabric component 20 is capable ofdefeating ballistic threats. In addition, the present invention'selastomeric coating component 10, situated on a ballistic fabric 20, iscapable of defeating pointed, sharp-cutting projectiles, such as thetypes of broadhead arrows that are portrayed by way of example in FIGS.9 through 11 . The present invention's elastomeric coating is thickenough to impede a broadhead arrow, and yet is thin enough to promotewearability as well as noninterference with the ballistic-protectivemechanism of the fabric-based component.

An inventive armor system may resist sharp or pointed weaponry in any ofvarious ways. FIGS. 13 through 16 exemplify possible dynamics of how aninventive armor may resist sharp or pointed weaponry. These examplesportray “non-infiltrative” inventive embodiments, that is, inventiveembodiments in which the elastomeric coating does not infiltrate to anyextent into the fabric component. In the light of the instantdisclosure, the ordinarily skilled artisan will appreciate that theinventive principles demonstrated in FIGS. 13 through 16 will similarlyapply to “infiltrative” inventive embodiments, that is, inventiveembodiments in which the elastomeric coating does to some extentinfiltrate into the fabric component.

As depicted by way of example in FIGS. 13 and 14 , respectively, uponimpact with an inventive armor, a broadhead arrow traveling in initialdirection d may ricochet (e.g., rebound or bounce) off astrain-rate-sensitivity-hardening elastomeric material coating 10/30,thus travelling divergently away from the inventive armor in a ricochetdirection r. As another example, an elastomeric coating 10/30 may resistpenetration in a manner resulting in breakoff of a tip portion 41 of anarrowhead 401, such as depicted by way of example in FIGS. 15 and 16 ,respectively.

As shown in FIGS. 15 and 16 , tip portion 41 breaks off of arrowhead 401while arrow 40 continues to traverse the inventive armor. Tip portion 41remains immovably captured within the elastomeric coating 10/30 and/orthe ballistic fabric 20, while the intact portion of arrow 40 continuesto travel approximately in direction d. Only a small portion ofarrowhead 401 pierces completely through the inventive armor, viz.,transpierce portion 43, which inwardly projects from the inside surfaceof ballistic fabric 20 and has a front breakoff edge 44. Under manycircumstances transpierce portion will protrude inwardly withoutsignificant personal injury, particularly if the wearer is also wearingpadding or other material beneath the inventive armor.

Accordingly, as diagrammatically illustrated in FIGS. 15 and 16 , thehard surface afforded by the elastomeric coating 10/30 enables theunderlying ballistic fabric material 20 to resist the degraded arrowheador any follow-on bullets or blast fragments such as from a warfighterscenario. Arrow 40 may experience (i) reduced velocity and/or (ii) tipbreakage, due to a strain-rate-sensitivity-hardening of the elastomericcoating that is associated with the impact. The broken piece(s) of thearrow tip become(s) lodged in the ballistic fabric-based component. Themajor portion of the arrow tip continues to travel through the ballisticfabric-based component at a reduced rate, but does not penetrate as faras it would have if the arrow tip were speedier and entirely intact. Theblunted arrow tip that remains after impact with the elastomeric coatingdoes not proceed as far through the ballistic fabric-based component, ascompared with what would occur upon encounter of the same arrow, at thesame speed, with the ballistic fabric-based component in the absence ofthe elastomeric coating.

Also referring to FIGS. 17 and 18 , inventive testing was conducted withrespect to inventive armor embodiments that included a ballisticfabric-based component 20 up to 0.4 inch thick. The experimental resultsindicate that a very lightweight nominal elastomeric coating ofapproximately 1/16 through 0.1 in on Kevlar® parts can afford, tolightweight tactical armor such as found in body armor and differenthelmet types, a significant protective quality against sharp-edged pointprojectiles. FIG. 17 conveys that inventive practice admits ofmultifarious combinations of the respective thicknesses of theelastomeric coating thickness and the fabric-based component. Asfrequently practiced the present invention provides for a thicknessratio in the approximate range between 0.15 and 0.35.

Inventive performance was investigated with respect to ballisticfabric-based components categorized in two discrete ranges of the poundsper square foot pressure unit (psf). The present inventors demonstratedthe effectiveness of an embodiment of an inventive armor system thatincluded a ballistic fabric-based component 20 construction on the orderof 1.8 to 2.3 psf in combination with a polyurea coating 10 on the orderof 0.08 to 0.10 inch thick. Further, the present inventors demonstratedthe effectiveness of an embodiment of an inventive armor system thatincluded a lighter ballistic fabric-based component 20 construction,viz., on the order of 1.3 to 1.7 psf, in combination with a polyureamatrix coating 30 on the order of 0.08 to 0.10 inch thick.

The experiments that were undertaken by the present inventors involvedtwo types of leftover panels from a Cooperative Research and DevelopmentAgreement (CRADA) program in which the U.S. Navy and DuPont Corporationcollaborated to investigate helmet technology. The panel of the firsttype represented a light advanced Kevlar® helmet architecture (about 2.0psf). The panel of the second type represented a very light Kevlar®construction (about 1.5 psf). It is noted that standard combat helmetscurrently used by the military have an areal density of about 2.2 psf.Razor-sharp broadhead arrows were used by the present inventors to testthe efficacy of inventive practice, in particular the effects ofinventive elastomeric coatings 10/30 in stopping penetration of thebroadhead arrows. The arrows were launched at 25 yards with 55 lb ofpull. The arrow used in the testing was a 100 grain broadhead with a 28¼inch shaft.

In the testing of the panel of the first type, half of the panel wascoated with a thin, nominally 1/16 inch coating of polyurea. Thispolyurea coating was an unfilled strain-rate-sensitivity-hardeningelastomer coating. As illustrated by way of example in FIG. 12 , thepenetration of the arrows into the uncoated half of the Kevlar® panelwas sufficient to pierce into the skull of a human wearing a helmetcorresponding to the uncoated half of the panel. In contrast, the arrowsjust bounced off the polyurea-coated half of the panel, such asillustrated by way of example in FIG. 13 .

In the testing of the panel of the second type, a particle-filledstrain-rate-sensitivity-hardening elastomeric matrix coating was addedto the panel to reach approximately a 2.0 psf level. The polyuria matrixcoating on the second panel, exemplified in FIG. 16 , was a polyureafilled with small glass microspheres constituting nominally 30 percent(weight percentage) of the overall weight of the elastomeric coating.The second panel's polyurea matrix coating 30 was produced by addingglass particulates 50 to a polyurea material constituent 10. The glassparticulates 50 were each up to 100 microns in diameter and overallconstituted up to 30 percent by weight of the polyurea matrix coating30.

As illustrated by way of example in FIG. 16 , arrows were able to piercethrough the particle-filled polyuria matrix coating and the very lightKevlar® material “backing.” However, the penetration level of each ofthe arrows was small, the projection distance less than the typicalthickness of the pads between the helmet shell and human skull intypical use of a conventional combat helmet. The tip of the most deeplypenetrating arrow was actually broken off while the arrow was passingthrough the elastomeric coating.

The present invention, which is disclosed herein, is not to be limitedby the embodiments described or illustrated herein, which are given byway of example and not of limitation. Other embodiments of the presentinvention will be apparent to those skilled in the art from aconsideration of the instant disclosure, or from practice of the presentinvention. Various omissions, modifications, and changes to theprinciples disclosed herein may be made by one skilled in the artwithout departing from the true scope and spirit of the presentinvention, which is indicated by the following claims.

What is claimed is:
 1. A composite armor system comprising: a ballisticfabric-based backing layer, said ballistic fabric-based backing layerhaving an areal density no greater than approximately 1.7 pounds persquare foot; and an elastomeric coating strike-face layer, saidelastomeric coating strike-face layer consisting essentially of aparticle-filled strain-rate-sensitivity-hardening elastomeric matrixmaterial and covering at least one area of said ballistic fabric-basedbacking layer, said particle-filled strain-rate-sensitivity-hardeningelastomeric matrix material having a combination of an elastomer matrixand a quantity of particles in said elastomer matrix, said quantity ofparticles by weight constituting no greater than approximately 50percent of the weight of said elastomer matrix; wherein in said at leastone area of said ballistic fabric-based backing layer: said elastomericcoating strike-face layer is bonded onto said ballistic fabric-basedbacking layer; said elastomeric coating strike-face layer does notinfiltrate into said ballistic-fabric-based backing layer; saidelastomeric coating strike-face layer and said ballistic fabric-basedbacking layer, in combination, have an areal density no greater thanapproximately 2.5 pounds per square foot; said elastomeric coatingstrike-face layer has a thickness no less than 0.06 inch; wherein, uponimpact by a sharp or pointed object, said elastomeric coatingstrike-face layer undergoes strain-rate-sensitivity hardening thatimpedes said sharp or pointed object.
 2. The composite armor system ofclaim 1, wherein in said at least one area said ballistic fabric-basedbacking layer has an areal density in the approximate range of 1.3 to1.7 pounds per square foot.
 3. The composite armor system of claim 1,wherein in said at least one area said quantity of particles constitutesa weight in the approximate range of 10 percent to 30 percent of theweight of said elastomer matrix.
 4. The composite armor system of claim1, wherein in said at least one area: said elastomeric coatingstrike-face layer has a thickness in the approximate range of 0.06 to0.12 inch; and said ballistic fabric-based backing layer has a thicknessin the approximate range of 0.2 to 0.5 inch.
 5. The composite armorsystem of claim 1, wherein in said at least one area: said elastomericcoating strike-face layer has a thickness in the approximate range of0.08 to 0.10 inch; and said ballistic fabric-based backing layer has athickness in the approximate range of 0.2 to 0.5 inch.
 6. The compositearmor system of claim 1, wherein said elastomer matrix is a polyurea. 7.The composite armor system of claim 1, wherein: said elastomer matrix isselected from the group of elastomers consisting of polyurea,polyurethane, and a mixture of polyurea and polyurethane; said ballisticfabric-based backing layer includes a fabric material selected from thegroup of fabric materials consisting of aramid, polyethylene, polyamide,polyester, polybenzobisoxazole, and glass.
 8. The composite armor systemof claim 1, wherein: said elastomer matrix is selected from the group ofelastomers consisting of polyurea, polyurethane, and a mixture ofpolyurea and polyurethane; said ballistic fabric-based backing layerincludes a fabric material selected from the group of fabric materialsconsisting of aramid, polyethylene, polyamide, polyester,polybenzobisoxazole, and glass; in said at least one area of saidballistic fabric-based backing layer: said elastomeric coating layer hasa thickness no less than 0.06 inch; said ballistic fabric-based backinglayer has a thickness no less than 0.2 inch; the ratio of said thicknessof said elastomeric coating layer to said thickness of said ballisticfabric-based backing layer is no less than 0.12.
 9. A composite armorsystem comprising: a ballistic fabric-based backing layer, saidballistic fabric-based backing layer having an areal density no greaterthan approximately 1.7 pounds per square foot; and an elastomericcoating strike-face layer, said elastomeric coating layer consistingessentially of a particle-filled strain-rate-sensitivity-hardeningelastomeric matrix material, said elastomeric coating layer covering atleast one area of said ballistic fabric-based backing layer, saidparticle-filled strain-rate-sensitivity-hardening elastomeric matrixmaterial having a combination of an elastomer matrix and a quantity ofparticles in said elastomer matrix, said quantity of particles by weightconstituting no greater than approximately 50 percent of the weight ofsaid elastomer matrix; wherein in said at least one area of saidballistic fabric-based backing layer: said elastomeric coatingstrike-face layer is bonded onto said ballistic fabric-based backinglayer; a portion of said elastomeric coating strike-face layerinfiltrates said ballistic fabric-based backing layer; an infiltrationregion is formed representing both a sublayer of said elastomericcoating strike-face layer and a sublayer of said ballistic-fabric-basedbacking layer; said infiltration region has a thickness in theapproximate range of 10 to 60 percent of the thickness of said ballisticfabric-based backing layer; said elastomeric coating strike-face layerand said ballistic fabric-based backing layer, in combination, have anareal density no greater than approximately 2.5 pounds per square foot;said ballistic fabric-based backing layer has a plurality of plies, saidplurality of plies including a front-most ply; said infiltration regionextends through approximately the entire said front-most ply; wherein,upon impact by a sharp or pointed object, said elastomeric coatingstrike-face layer undergoes strain-rate-sensitivity hardening thatimpedes said sharp or pointed object.
 10. The composite armor system ofclaim 1, wherein in said at least one area of said ballisticfabric-based backing layer the ratio of said thickness of saidelastomeric coating strike-face layer to said thickness of saidballistic fabric-based backing layer is in the approximate range of 0.15to 0.35.
 11. The composite armor system of claim 9, wherein in said atleast one area: said elastomeric coating strike-face layer has athickness in the approximate range of 0.06 to 0.12 inch; and saidballistic fabric-based backing layer has a thickness in the approximaterange of 0.2 to 0.5 inch.
 12. The composite armor system of claim 9,wherein in said at least one area: said elastomeric coating strike-facelayer has a thickness in the approximate range of 0.08 to 0.10 inch; andsaid ballistic fabric-based backing layer has a thickness in theapproximate range of 0.2 to 0.5 inch.
 13. The composite armor system ofclaim 9, wherein said elastomeric matrix material is a polyurea.
 14. Thecomposite armor system of claim 9, wherein: said elastomeric coatingstrike-face layer is selected from the group of elastomeric materialsconsisting of polyurea, polyurethane, and a mixture of polyurea andpolyurethane; said ballistic fabric-based backing layer includes afabric material selected from the group of fabric materials consistingof aramid, polyethylene, polyamide, polyester, polybenzobisoxazole, andglass.